com.getperka.flatpack.codexes.EntityMapCodex Maven / Gradle / Ivy

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/*
 * #%L
 * FlatPack serialization code
 * %%
 * Copyright (C) 2012 Perka Inc.
 * %%
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * #L%
 */
package com.getperka.flatpack.codexes;

import java.io.IOException;
import java.util.Map;

import javax.inject.Inject;

import com.getperka.flatpack.FlatPackVisitor;
import com.getperka.flatpack.HasUuid;
import com.getperka.flatpack.ext.Codex;
import com.getperka.flatpack.ext.DeserializationContext;
import com.getperka.flatpack.ext.JsonKind;
import com.getperka.flatpack.ext.SerializationContext;
import com.getperka.flatpack.ext.Type;
import com.getperka.flatpack.ext.TypeContext;
import com.getperka.flatpack.ext.VisitorContext;
import com.getperka.flatpack.util.FlatPackCollections;
import com.google.gson.JsonElement;
import com.google.gson.JsonPrimitive;
import com.google.gson.stream.JsonWriter;
import com.google.inject.TypeLiteral;

/**
 * Provides a mapping of entities to arbitrary values.
 */
public class EntityMapCodex extends Codex> {
  private EntityCodex keyCodex;
  private Codex valueCodex;

  protected EntityMapCodex() {}

  @Override
  public void acceptNotNull(FlatPackVisitor visitor, Map value,
      VisitorContext> context) {
    if (visitor.visitValue(value, this, context)) {
      for (Map.Entry entry : value.entrySet()) {
        context.walkImmutable(keyCodex).accept(visitor, entry.getKey());
        V oldValue = entry.getValue();
        V newValue = context.walkSingleton(valueCodex).accept(visitor, oldValue);
        // Object comparison intentional
        if (oldValue != newValue) {
          entry.setValue(newValue);
        }
      }
    }
    visitor.endVisitValue(value, this, context);
  }

  @Override
  public Type describe() {
    return new Type.Builder()
        .withJsonKind(JsonKind.MAP)
        .withMapKey(keyCodex.describe())
        .withMapValue(valueCodex.describe())
        .build();
  }

  @Override
  public String getPropertySuffix() {
    return valueCodex.getPropertySuffix();
  }

  @Override
  public Map readNotNull(JsonElement element, DeserializationContext context)
      throws IOException {
    Map toReturn = FlatPackCollections.mapForIteration();
    for (Map.Entry entry : element.getAsJsonObject().entrySet()) {
      context.pushPath("." + entry.getKey());
      try {
        K key = keyCodex.read(new JsonPrimitive(entry.getKey()), context);
        V value = valueCodex.read(entry.getValue(), context);
        toReturn.put(key, value);
      } finally {
        context.popPath();
      }
    }
    return toReturn;
  }

  @Override
  public void writeNotNull(Map object, SerializationContext context) throws IOException {
    JsonWriter writer = context.getWriter();
    writer.beginObject();
    for (Map.Entry entry : object.entrySet()) {
      String key = entry.getKey().getUuid().toString();
      context.pushPath("." + key);
      try {
        writer.name(key);
        valueCodex.write(entry.getValue(), context);
      } finally {
        context.popPath();
      }
    }
    writer.endObject();
  }

  @Inject
  @SuppressWarnings("unchecked")
  void inject(EntityCodex keyCodex, TypeLiteral valueType, TypeContext typeContext) {
    this.keyCodex = keyCodex;
    this.valueCodex = (Codex) typeContext.getCodex(valueType.getType());
  }
}